Paint spraying apparatus



NOV. 13 1934. G. A, YEDD immsrrmme APPARATUS Fnea May 8. 1931 2Sheets-Sheet 1 Ewing R. v m 0 UAW 1 r. Y M 4 H B Nov. 13, 1934. D1,980,464

' rum- SPRAYING APPARATUS Filed May 8. 1931 ZSheets-Shdet 2 ATTORNEYPatented Nov. 13, 1934 UNITED STATES PATENT OFFICE The invention relatesto an improved paint spraying apparatus.

An object of the invention is to provide a generally improved sprayingapparatus ofthe type described for more or less universal use inhandling both viscous and non-viscous liquids.

Another object of the invention is to provide for a multiple-stageatomization of the liquid during its passage from a supply reservoirthereof to its point of final disposition.

A further object of the invention is to provide for a diluting of theliquid with air to increase the fluidity thereof for its delivery to adischarge element disposed at a distance from the reservoir.

Yet another object is to provide a generally improved sprayer or spraygun for use in apparatus of the class described.

A still further object is to provide a spray gun having an improvednozzle for delivering streams of various characteristics withoutnecessitating a change of nozzle members.

An added object is to provide in a high pressure apparatus of the classdescribed means for increasing or boosting the discharge pressure of thespray gun element of the apparatus.

The invention possesses other objects and features of advantage some ofwhich, with the foregoing, will be set forth or be apparent in thefollowing description of a typical embodiment of the invention which isillustrated in the accompanying drawings, in which,

Figure 1 is a plan view of a spray gun of apparatus embodying theinvention.

Figure 2 is a sectional elevation of the spray gun at the line 2-2 inFigure 1, a nozzle valve of the gun being closed.

Figure 3 is a sectional view taken at 3-3 in Figure 2.

Figure 4 is a perspective view of a nozzle ele- 4 merit of the spraygun.

Figure 5 is an enlarged fragmentary view of the nozzle tip assemblyshown in Figure 2, the valve thereof being shown as slightly opened.

Figure 6 is an elevation of a complete appa- 5 ratus embodying thefeatures of the present invention. Y

Figure '7 is'an enlarged view of the nozzle portion shown in Figure '5,and discloses an accessory tip member mounted on said nozzle.

Figure 8 isa plan section through a tank head control valve of theapparatus.

The various structural and operative features of the present inventionare generally disclosed in the showing of Figure 6 wherein apparatus isshown for delivering liquid from a tank or reservoir 11 through a tankhead control device 12 and a flexible hose 13 to a spray gun 14. Thedisclosed apparatus is designed for high pressure operation by means ofcompressed air re- 7 ceived from a tank 15 or other suitable source. Inthe present arrangement the tank 15 is shown as connected to thereservoir 11 and spray gun 14 by means of hoses 16 and 1'7 respectively.In the operation of the device the liquid from the tank 11 is arrangedto be atomized and diluted with air in its passage through the controldevice 12 and also in the spray gun 14. Furthermore,

a third atomization of the liquid is arranged to be effected as the sameis discharged from the spray gun. Besides the atomization produced inthe apparatus, certain other favorable results are accomplished throughcertain specific structural and operative features resident in thecontrol device 12 and the spray gun 14.

Referring to the structure of the control device 12, the same beingshown in section in Figure 8, it is noted that said device comprises agenerally T-shaped body member 18 providing an air supply passage 19which is branched to discharge air downwardly through a duct 20 into thetop of the tank and through a horizontal duct 21 into a passage 22 ofthe device. The passage 22, it

is noted, is connected with a riser pipe 23 extending upwardly fromwithin the liquid in the I tank 11 whereby the pressure in the tank isarranged to deliver liquid into the passage 22, and the air duct 21terminates in the nozzle 24 disposed axially in said passage. It isnoted that the various ducts and passages now described are all providedin relatively fixed parts of the body element 18 of the control device.

The forward end of the nozzle 24 is conically tapered for seatedengagement in the opposed end of the bore 25 of a tubular member 26,said member being adjustably and slidably engaged in the passage 22whereby the conical bore portion thereof may be variably disposed withrespect to the tip ofthe nozzle 24; in thismanner the nozzle 24 andmember 26 are cooperative as a valve means to control the flow of liquidfrom 190 the passage 22 into the bore 26. When liquid .flow is permittedfrom the control device, the discharge of air from the nozzle 24 intothe bore 25 is arranged to eflect an atomizing and aeration of theliquid in said bore. A valve 2'7 is operative in the duct 21 whereby theflow of air and liquid into the bore 26 may be independently controlled,it being noted that either flow may be completely cutoff.

The member 26, it is noted, slidably fits the no bore of the passage 22at the inner end thereof and is reduced outwardly of itspassage-engaging 5 threadedly mounted on the forward end of the bore 20and is operative through the packing 29 in the stuffing box to determinethe position of the member 26 with respect to the nozzle 24, it beingnoted that the pressure in the passage 22 is arranged to urge saidmember to its outer position; in this manner the member 26 is sealedlyand adjustably engaged in the bore of the passage 22. The protruding endof the member 26 carries a coupling element 31 for use in attaching thehose 13 thereto. The specific structure and use features of the controldevice 12 it is noted, are set forth in greater detail in my copendingapplication, Ser. No. 535,867, filed May 8, 1931.

Referring now to the structure of the spray gun 14, it is noted that thesame is generally T-shaped to provide integrally associated barrel andgrip portions 33 and 34 respectively, said portions being of appropriateshapes for their respective purposes. The grip portion 34 may ifdesired, slope rearwardly from its point'of juncture with the barrelportion 33 whereby a desired pointing of the latter portion may be morenaturally effected by a person holding the-spray gun by means of thegrip; this condition is shown in the present structure wherein the anglebetween the grip portion and the forward part of the barrel somewhatexceeds ninety degrees. Intersecting passages 35 and 36 are provided inthe barrel and grip portions 33 and 34 respectively, whereby acontinuous fluid passage is provided from the butt of the grip portionto a nozzle end of the barrel.

The grip passage 36, it is noted, provides a mixing chamber havingportions 37 and 38 of different diameters and connected by a bevel 39,the chamber 38 being nearest the inlet end of said passage and being ofgreatest diameter; An injector nozzle 41 is mounted in the chamber 38'for longitudinal adjustment therein, said nozzle being conicallytapered at its forward and discharge end for seating against the bevel39. Intermediately of the nozzle member, a portion of the same isradially expanded to provide a collar 42 for a close sliding fit in thechamber bore whereby the nozzle is held in axial alignment with thechamber 38 as it is moved to and from the bevel 39.

'An inlet duct 43 of the gun grip portion is directed obliquelyforwardly into the portion of the chamber 38 defined between the bevel39 andthe nozzle collar 42, and a connecting member 44 engages the outerend of saidduct for use in attaching the hose 13 thereto. An axiallyperforated screw element 45 engages in the forward end of the nozzlebore, said element being operative to determine the maximum air flowfrom the nozzle and the head thereof being operative to restrict thepassage for liquid provided along the bevel 39 in a manner to facilitatean atomizing of the liquid as .it discharges into the chamber 37, itbeing noted that the nozzle tip is normally withdrawn from engagementwith said.

bevel which constitutes a valve seat at which liquid supply may be cutoff. The outer nozzle end carries a coupling element 45 for connectingthe air hose 17 thereto.

Means are preferably provided for sealing and securing the nozzle inadjusted position in the chamber 38. As shown, soft packing 46 isdisposed in the chamber space rearwardly of the nozzle collar 42, and agland cap 4'7 is threadedly mounted on the grip extremity for engagingand compressing said packing in said space. By screwing up the said cap,the pressure exerted on the annulus of packing is operative against thenozzle collar 42 to move the nozzle inwardly toward the bevel 39' asdesired, it being noted that the pressure of liquid in the chamber 38 isarranged to urge an outward movement of the nozzle. In this manner, thenozzle is sealed in the chamber bore which carries it, and at the sametime is arranged for adjustment to vary the quantity of liquid suppliedto the passage 36.

It is noted that the described injector device by which the liquid fromthe hose 13 is atomized and aerated within the spray gun independentlyof its treatment at the control device 12 also serves to create anincreased and forwardly directed flow pressure in the gun, whereby anincrease of the discharge pressure is effected and a somewhat lowerpressure may be obtained in the hose 13 than is required or desired inthe gun. This provision for boosting the operating pressure in the gunis understood to constitute an .important operative feature of thepresent apparatus.

A discharge orifice 51 is provided atlthe forward end of the barrelportion 33 andthrough which the aerated liquid is arranged to be ejectedin a stream of variable characteristics. The effective opening of saidorifice is considerably less than a section of the adjacent portion ofthe barrel bore 52, the barrel bore being cylindric.

Preferably and as shown, the orifice 51 is provided in a tip member 53of special form, the structural details thereof, being brought out inFigures 4, 5 and 7. In its present embodiment, the tip member 53 isgenerally cup shaped and comprises a tubularportion 54 for fittedinsertion within the outer end of the barrel bore 52 and an expandedforward portion 55 which provides a shoulder 56 for engagement againstthe barrel extremity. An axially perforated cap member 57 threadedlyengages the forward barrel portion externally thereof for clamping themember 53 against the barrel end. As particularly shown, the outer andforward face of the member 53 is cylindrically countersunk whereby theannular cap head is arranged to engage the resulting annular flange ofthe member 53 when the same is in its mounted position on the barrelend.

The orifice 51 is provided axially in the transverse wall 58 of themember 53 and comprises conical bore portions 59 and 61 intersecting ina line intermediately of the orifice ends, the eflective orifice beingleast at said line. Preferably, and as shown, the conical angle of theinner bore portion 59 is of theprder of sixty degrees, while that of thebore portion 61 is of the order of one hundred and twenty degrees; inthis manner, the angle of the distinct and sharp edge 62 deflnedat theline of intersection of the bore portions is of the order of ninetydegrees.

A cylindric valve stem 63' of somewhat lessdiameter than the barrelbfc'ire 52' is mounted in the barrel in coaxial relation therewith. The

.forward end of said valve stem is arranged to slidably fi-tjnthe boreof the tubular portion 54 o f the tip member 53. Rearwardly of thejuncture 'of the grip passage 36 with the barrel passage 35,

the valve stem 63 extends through a stuffing box 64 to a point beyondthe rearward end of the barrel; -'in this manner the valve stem is heldfor axia'l 'reciprocation in the barrel. A conical valve 65 is providedat the forward end of the valve stem 63 for movement to and from theconical bore portion 59 of the member 53, said valve being complementaryto said bore portion whereby the bore portion is thus arranged to serveas a seat for the valve. A means for controlling the operativedisposition of the valve 65 is hereinafter described.

Longitudinal kerfs 66 are provided in the tubular portion 54 of themember 53 and extend from the inner end of the member 53 to a greater orless degree into the seat provided by the conical bore portion 59; inthis manner, when the valve 65 is unseated. the liquid in the barrelpassage 35 is arranged to be delivered along the stem and forwardly ofthe valve in a plurality of laterally separated streams which aredirected radially inwardly between the valve and seat and unite forprojection from the discharge orifice 53. In the present instance, fourkerfs 66 are provided and their inner ends are substantiallyperpendicular to the barrel axis.

It will now be particularly noted that the discharge valve provided bythe described structure, besides accomplishing a final atomization ofthe liquid, is arranged to produce discharge streams of variedcharacteristics, and that the degree of variation is the extreme rangerequired in spray guns; with spray guns of usual structure, however,said extreme range may usually be accomplished only by aninterchangeable use of a plurality of different tip members. In thepresent structure, the spread of a discharged stream will generallydecrease as the valve 65 is unseated. By appropriately varying thesettings of the control head valves and the valves of the spray gun,discharge streams may be provided having distinct outside boundaries andwithout producing side mists, such mists representing a waste ofmaterial and preventing a completely controlled depositing of thepainting liquid. The present device is arranged to produce a solid andhomogeneous Jet which is so sharply defined that writing may be executedtherewith on a receiving surface with a relatively non-flaring jet. Itis noted that the conical angularity of the outer portion 61 of thedischarge orifice is such that none of the discharging liquid contactsthe surface of the same.

In effecting the double aeration and triple atomization of a paintingliquid by the described apparatus, an operative condition of importanceis the fact that the spray gun discharge pressure is arranged to be verymuch higher than is usual for spray guns for the same purpose. Thepresent spray gun is arranged to operate under pressures varying fromninety pounds per square inch to six hundred fifty pounds per squareinch, with one hundred fifty pounds per square inch the usual operatingpressure. Under the foregoing high-pressure operating conditions of thespray gun, the discharged jet of painting material is accuratelyprojected for a considerable distance without losing its clearness ofdefinition, whereby a minimum waste of the painting material results.

In view of the high pressures which are arranged to obtain within thebarrel passage 35.

of the spray gun, the valve stem packing and control means are ofspecial design. As particularly shown in Figure 2, the stufllng box 64is defined between gland rings 67 slidable on the stem 63 and between anenlarged bore portion of the passage 35 and the stem, a forward movementof the forward packing ring 67 being limited by its engagement with thestep or shoulder provided at the forward end of the enlarged passageportion at the stuffing box. A cup-shaped gland member 68 threadedlyengages in the bore of the passage 35 rearwardly of the stuffing boxportion thereof and with its forward end engaging the rearward ring 67for compressing suitable soft packing 69 within the stuifing box spacebetween the rings and to a required degree. It is noted that the freedomof the forward packing ring 67 permits its displacement to furthercompress the packing in the stuffing box by reason of the pressure inthe passage 35 whereby the arrangement is adapted for automaticallymain,- taining a seal for the valve stem.

Rearwardly of the stufllng box 64, the valve stem 63 is reduced toprovide a shoulder 71, and a helical compression spring '72 is operativewithin the member 68 between said shoulder and the head of the member tourge a maintenance of the valve 65 in seated relation to the seat 59 ofthe nozzle tip member 53. The rearward end portion of the valve stemextends through and from an axial perforation of the member 68, and itsprotruding portion is threaded to receive a knurled nut 73.

It will now be noted that a valve-opening displacement of the stem 63 isarranged to be effected by and upon an appropriate rocking of a triggermember 74 pivoted to the barrel portion of the spray gun, said triggerarranged to be operatively rocked against the resistance of the spring72 for opening said valve. As shown, the trigger member 74 is forked orbifurcated to span the barrel 33, and the fork 'portions'75 of themember '74 are pivoted at their extremities to a laterally projectingear 76 of the barrel, said ear lying at the opposite side of the barrelfrom the gun grip portion 34 for swinging theretoward by use of thefingers of a hand grasping the grip, the grip serving as a stop to limitthe degree of rocking of the trigger member, as is indicated in dottedlines in Figure 2.

A strut means is operative between the trigger member and the protrudingvalve stem portion whereby a rocking of the trigger toward the grip isarranged to unseat the valve 65 to a maximum degree determined by thepermitted operative movement of the trigger. As particularly shown,

said strut means comprises a U-shaped member 77 having its side portions78 mutually parallel and engaged in slideways 79 provided in oppositesides of the barrel 33 and its cross portion, or head, 81 perforated toreceive the valve stem 63 therethrough with said head disposed forwardlyof the nut 73. Ears or trunnions 83 extend outwardly from the forwardends of the strut portions 78 and into the paths of'movement of thetrigger portions '75 for engagement thereby as the trigger is rockedtoward the grip. In this manner, the strut member is directly operativebetween the trigger and the valve stem nut 73, and adjustment of saidnut on the valve stem is understood to control the permitted operativemovement of the trigger from its normal forward position to a contactwith the spray gun grip portion. It is noted that the presentarrangement cannot at any time prevent a return of the valve to itsseated position in the nozzle outlet when the trigger is released, andan 'operator may at the same time be assured of a constantand adjusteddegree of opening of the valve by holding the trigger back against thegun grip necessary to mount a suitable auxiliary tip on the Ibarrel-forwardly of the tip member 53. As partic'ularly shown in Figure7, a tip member is provided, said tip member of general cup shape andhaving a dome-shaped forward end portion 86 provided with a radial kerf87 of desired angu lar length. A flange 88 extends radially from thebase of the member 85, said base and flange being arranged for acentered seating in the forward depression of the member 53, and. thecap 5'! being utilized to engage the flange 88 to secure the ation willbe readily understood by those skilled in the art to-which the inventionappertains. and

while I have described the principle of operation, together with thedevice which I now. consider to be the best embodiment thereof, I desireto have it understood that the device shown is merely illustrative, andthat such changes may be made,

'whendesired: as fall within the scope of the appended claims;v

Having thus described my invention. Iclaim as new and desire to secureby Letters Patent of the United States the following:

1. In a spray gun ofthe type described; a body providing a tubulardischarge barrel. a valve stem disposed axially in said barrel and ofless size than the body bore whereby'to define a fluid passagetherealong. a conical valve carried at the forward end-of said stem, anda member fixed at the forwardend of said barrel and comprising a sleeveportion flttedly engaged in the barrel bore and 'slidably receiving thestem and a. transverse outer end portion providing a discharge portaxially therethrough and for control by said valve,

said flrst portion of said member having longitudinal slots to providelaterally spaced fluid passages along the valve stem portion, said slotsterminating at the inlet mouth of said discharge port whereby fluiddischarged therefrom is directed radially inwardly against said valve.

2. In a spray gun of the type described, a body providing a tubulardischarge barrel, a cylindric valve stem disposed axially in said barreland of less size than the body bore whereby to define a fluid passagetherealong, a conically tapered valve carriedaat the forward end of saidstem, and a member flxed at the forward end of said barrel and having asleeve portion thereof flttedly engaged in the barrel bore and slidablyreceiving said stem and a transverse outer end portion providingn'adischarge port axially therethrough and for control by said valve, saidfirst portion of said member being longitudinally kerfed to providelaterally spaced fluid passages along the valve stem portion thereatand-for discharge forwardly of said valve when the same is unseated. andthe bore of said port having an inner conical portion providing a seatfor said valve and an outer conical portion intersecting the inner-boreportion at an angle 'of the order of ninety degrees inan edge definingthe port point of greatest restriction.

GUY A. YEDD.

